We derive the optimal treatment rules using the proposed method, the [1]} method, the [2]} method, and the zero-order model. The value of the observed policy—the combination of randomization and physician's judgement—is estimated and is compared with the other rules. As in Section , the [1]} method was implemented using two different Q-function approximations: a linear model and a random forest. Because the [2]} method was implemented using R package DTRreg the current version (1.7) of which allows binary treatment arms only, the method was applied after dichotomizing the initial treatment according to inclusion of all-trans retinoic acid.
